This invention relates generally to printers utilizing continuous pin-feed forms, and more particularly to a method and apparatus for splicing said forms within such printers.
High-speed laser electrographic printers, such as the IBM 3800, are often used to process large printing jobs for institutions such as banks. The process of feeding paper to such high-speed printers, or other machines which continuously process paper or other webbed materials at high speeds, has been typically accomplished by supplying a continuous web of material to the printer or processing machine and providing means for continuous removal and collection of the processed web. Some such machines are so constructed and operated to permit the continuous feeding and removal of the web with no down-time required to perform paper handling tasks.
The IBM 3800, however, like other such high-speed printers being operated today is not capable of being fed a continuous web of paper, but instead is normally operated by supplying a stack of folded web sheets, running the printer to process the stack, and then stopping the printer to take out the processed stack, the sequence being repeated as necessary to complete the printing job. Such high-speed printers conventionally have paper feed apertures and discharge apertures positioned in recesses within the machine which make the continuous feeding and removal of the paper virtually impossible. Similar such printers are also produced by Storage and Technology Corporation as the 6100 Printing Subsystem. Further information pertaining to the IBM 3800 printer and related support systems is available in the IBM publication GA32-0049-3, "IBM 3800 Printing Subsystem Models 3 and 6 Introduction," GA32-0050-2, "Reference Manual for the IBM 3800 Printing Subsystem Models 3 and 6," GA 32-0068-2, "IBM 3800 Printing Subsystem Models 3, 6, and 8 Operator's Guide," and GH20-9158-6, "Document Composition Facility General Information," which are incorporated herein by reference. As well, further information pertaining to the 6100 Printing Subsystem and related support systems is available in the Storage Technology Corporation publications P/N 3825131501B, "6100 Printing Subsystem Paper Specification Manual," P/N 3825131601, "6100 Printing Subsystem Form Design Guide," and P/N 3825118701, "6100 Printing Subsystem Operators Manual and Product Description Manual," each of which is incorporated herein by reference.
One problem typically encountered in any of the above described printers is the necessity to splice a fresh stack of continuous pin-feed forms to the expended stack of continuous pin-feed forms previously processed through the printer. For example, splices must be made carefully because they are critical to good machine performance. If a paper jam results from a poor splice, care must be taken to remove all pieces of tape and its adhesive residue from the machine, especially from the transfer station, fuser station, and continuous forms stacker. Paper jams may result from two basic causes. That is, if the length of tape used to splice the forms is longer than the width of the forms themselves, a potential exists for the tape or its adhesive to jam the printer as discussed immediately herein above. On the other hand, if the length of tape used to splice the forms is too short (i.e., not long enough to span the entire width of the forms), the unspliced corners of the forms may tend to fold back and become jammed within the printer. It is, therefore, desirable to provide a method and apparatus for splicing continuous pin-feed form which minimizes paper jams resulting from poor splices within high-speed printers.
In the IBM 3800, as in other similar such printers, splicing of the forms must take place within recessed areas of the printer. That is, the new paper must be first threaded up to the splicing station, making sure that the fold of the paper that is in the printer and the fold of the new paper are the same. If the folds are not alike and the splices made, the resulting stack of continuous pin-feed forms will be incapable of being stacked after processing in a conventional continuous forms stacker. A vacuum is then applied to a tape slot, with the splicing tape being placed thereafter in the slot with its adhesive side up. The splice is then made, the vacuum removed, and the printing operation continued. As is evident from this description, not only is the splicing process of continuous pin-feed forms in IBM 3800-type printers complicated through the necessity of first feeding the new paper up to the splicer, but it is also complicated through its requirement to utilize a vacuum system for holding the tape. Furthermore, personnel performing the splicing operation are required to do so in cramped quarters, thus increasing the chances for a poor splice which could result in paper jams. It would, therefore, also be desirable to provide a method and apparatus for splicing continuous pin-feed forms which could be accomplished external to the printer.
One prior art approach to the problem of providing a splicing station external to the printer is marketed by Acme Visible Records, Inc., and is known as a "Laser Feed" system. Such an apparatus and method for feeding a series of continuous pin-feed forms to a high-speed printer, utilizing auxiliary equipment positioned adjacent the printer, is described in U.S. Pat. No. 4,256,248, issued Mar. 17, 1981 to Lapp et al, and its reissue, U.S. Pat. No. Re. 31,210, reissued Apr. 19, 1983. The auxiliary equipment as described therein permits continuous splicing of webbed portions and, thus feeding of a continuous web to the printer, and intermittant removal of the webbed portions in such a manner that the printer may be run continuously without stoppage for feeding or removing the web. However, the apparatus disclosed in U.S. Pat. No. 4,256,248 and U.S. Pat. No. Re. 31,210 is complicated and bulky in nature, taking up virtually the same amount of space as the printer itself. Furthermore, the method as claimed therein requires the sequential splicing of a plurality of stacks of continuous pin-feed forms paper, but does not provide for the accurate placement of such splices to insure that paper jams do not occur. A similarly external but complicated apparatus for splicing continuous pin-feed forms is shown and described in U.S. Pat. No. 4,564,184, issued Jan. 14, 1986 to Rumpel.